A black box installed in a car to reduce insurance costs is believed to have saved the life of a Leatherhead student.

Max Charles, 20, was involved in a serious car crash, which left him with a brain injury, and led to him being put into a medically induced coma for five days.

In the early hours of November 28, 2013, Mr Charles was driving back from a nightclub when his car came off Kingston Road and crashed into a tree.

He was left lying on his own in the mangled vehicle with a serious brain injury, when the black box informed his insurance company that he had been in a crash.

His insurance company, Drive Like A Girl, was notified of a heavy collision – a 10G impact – and the company contacted the emergency services.

The GPS signal gave an exact location and ambulances were on the scene in minutes.

Mr Charles said: “I do not remember a lot about what happened on the night. I remember driving to Kingston to meet my mates, getting to a night club and dancing.

“I do not recall anything else that night. I do not know when I left the club, how I drove home. I only remember waking up at St George’s hospital in Tooting.

“I did not know who I was, who my family was or where I was, it was very scary.”

Mr Charles was in a coma for five days in hospital. After the event, he was told that when paramedics found him, he was only about 25% conscious, agitated and very angry.

He said: “That is why they put me in a medically induced coma. I was then airlifted to hospital.”

Police took blood samples from Mr Charles and tests revealed that he had no alcohol or drugs in his system, apart from the ketamine the ambulance crew had given him at the scene.

It is believed that he had fallen asleep at the wheel on his way home from his night out, coming off the road at 4am.

Because of the early hour of the crash, no other drivers saw the accident, Mr Charles was not visible from the quiet road he had been driving down and it could have been hours before he was discovered.

The small box was the only thing alerting the world to his situation.

Emergency services found his silver Vauxhall Corsa in a field, with Mr Charles slumped over the wheel. The roof of the car had to be removed to get him out.

Mr Charles said: “I simply got the black box to keep my insurance down. I did not know anything about the emergency services alarm feature. To find that out after the crash was an actual moral booster in a way.

“I was very lucky to have that black box. I have another car now, a Ford Focus, and I made sure I have a new black box in it. I would urge young drivers to get a black box. I am sure I would be dead if I did not have it.

“I know parents of my friends who drive are insisting they get one after they heard my story. It really is a life saver.”

The lifesaving black box is normally used to monitor young motorists’ driving habits. If you are a good driver, your insurance will come down, but if you are a poor driver, often speeding or involved in small bumps or scraps, this will automatically inform your insurers who will demand an explanation and may put up your premiums.

After the collision, Surrey Police tweeted a thank you to his insurance company, saying: “Thanks to Drive Like a Girl, who rang us when they detected an impact. Without their help, we would not have found the car and driver so quickly.”

Mr Charles was in hospital for a further two and a half weeks before being released.

It was a long road to recovery for the student, who received extensive physiotherapy, psychotherapy and regular neurology appointments after leaving hospital.

Mr Charles is now training to be a painter and decorator at the Queen Elizabeth’s Foundation Vocational Services in Leatherhead.

However, after having a lucky escape, he is still struggling to come to terms with the enormity of what happened.

He suffers from flash backs and headaches and has emotional problems as a result of what happened to him.

He said: “The first six months after coming out of hospital was hard. It has been a struggle with my family ever since the crash. I suffered from anxiety before the accident and this has made it worse. I am seeing a psychotherapist every week to help me deal with that.

“I still get very irritable at times and lose my temper, but I think that may be because of the brain injury I received in the impact.

“But I am lucky to be here. I just hope other people will learn from my story and get a black box installed in their car.”